Still, a number of loan deals, free transfers and low-cost moves have gone through this month, with the necessity to strengthen squads all the great in an injury-hit 2020/21 campaign. Here's a look at 17 deals, including Middlesbrough, that could still go through before Monday's transfer deadline:
1. Scott Twine - Swindon Town to Luton Town
The League One ace is attracting a lot of interest, with Luton Town believed to be in the running along with Reading, Brentford and QPR. His manager has hinted that a deal could happen, but a suitable bid is yet to be lodged. Photo: Alex Davidson
2. Ben Davies/Ben Pearson - Preston to Celtic
The Preston duo are out of contract in the summer, and Celtic have been heavily linked with the pair throughout the month. The former looks most likely to leave, but Bournemouth could move for both of them before the deadline. Photo: Lewis Storey
3. Kyle Joseph - Wigan Athletic to Barnsely
The Tykes are stepping up their efforts to bring in Wigan's teenage striker, after seeing a £500k bid reportedly turned down. However, Celtic, who seem to be after everyone this month, are also rumoured to be interested. Photo: Lewis Storey
4. Nathan Collins - Stoke City to Burnley/Arsenal
The Potters want to keep their teenage star until the summer, but could crumble if a lucrative late offer comes their way. Burnley are believed to have recently had an offer of around £4.5m turned down this month. Photo: George Wood